Remove command line options:

--cfg-get
--check-config
--config
--init-storage

- these are gone forever, in preparation for config-less start.

--background --  move to tarantool.cfg for now, in the future
it will be part of Lua config.

Make #! mandatory - if the server is started without #!, it's
only possible to query its version or get startup help (--version
and --help are the only remaining supported options).

When #! is present, do not parse options, pass them wholly to the
script at hand.

Add helper scripts to test suites, to start/stop the server.
For now, the scripts are empty, in the future they will be
merged with a respective config file.